Hydraulic system for actuating the tool-carrying beam of sheet bending machines



June 10, 1952 c.. J. RHODES 2,599,781 HYDRAULIC SYSTEM FOR ACTUATING THE TOOL-CARRYING BEAM OF SHEET BENDING MACHINES Filed May 25, 1949 5 Sheets-Sheet l lm enfr June 10, 1952 c. J. RHODES 2,599,781

HYDRAULIC SYSTEM FOR ACTUATING THE TOOL-CARRYING BEAM OF SHEET BENDING MACHINES Filed May 25, 1949 5 Sheets-Sheet 2 F76] .Cont! g3 r------- I I I I l I I I I 70 I I U T3 L5 '11. a eh I I I 25 IO 0 1 1 4/? I I :0 O; l I I l 23 1 I E] 1 IL I J I F n- 7 Mww'fior June 10, 1952 c. J. RHODES HYDRAULIC SYSTEM FOR ACTUATING THE TOOL-CARRYING BEAM 0F SHEET BENDING MACHINES 5 SheetsSheet 5 Filed May 25, 1949 ln vnja 6 %/0d ,2. r. 5 I j afneys n 0. 19 c J. RHODES 2,599,781 I 1 HYDRAULIC SYSTEM FR ACTUATING THE TOOL-CARRYING BEAM OF SHEET BENDING MACHINES Filed May 25, 1949 5 Sheets-Sheet 4 ca/ZZWg W64.

5 flzM Madd June 10, 1952 C. J. R 5 HYDRAULIC SYSTEM FOR ACTUATING THE TOOL-CARRYING BEAM OF SHEET BENDING MACHINES Filed May 25, 1949 5 Sheets-Sheet 5 Patented June 10, 1952 attan;

HYDRAULIC; svs 'rnmron ACQTU-AT-ING. THE

TOOL-CARRYING BEAM F SHEET BEND- I'NGv MACHINES Charles ios'eph Rhodes, Wakefield n slanc Application May 25, 1949, Serial No. 95,292 In Great. Britain Aprit 4, 19.4.9

T s n ion. relates to. impro e en s. i a d rel t to m chines fo bend ng s o ts and P ates of me a n ar kn n for e d n eets and plates. o meta in. which the eam, i h is raised and lowered by a hydraulic system, earries an upper moving bending tool co-operating with a lower, fixed bending tool on which the Pla e r s e t be b t pos tioned. f he beam moves with a rapid downward stroke, as is desirable for speed of; operation the moving bending tool comes forcibly into contact with the plate or sheet and may buckle or otherwise damage the latter.

According to the present invention, in a mas chine for bending sheets and plates of metal; the beam is rai ed and lowered by a hydraulic system which is controlled in accordance with the position of the beam so as to slowdown the downward movement of the beam when the lat-1 ter reaches a selected distance from the bottom of its stroke.

By suitably selecting the distance from the bottom of the stroke at which'the beam is slowed down, according to the character of the bending tools andthe nature and thickness of the plate orsheet to be bent, the upper bending tool may be brought relatively gently into contact with the plate or sheet whilst. maintaim'hg a rslae tively high speed of operation.

The hydraulic system may be controlled by a flow-regulating valve actuated by a control member which is adjustable with respeot to, the beam to vary the distance from the bottom of the stroke at which the beam is slowed down, The control member may be a cam member, adjustably mounted on thebea'm, col-roherating with a cam follower member operatively con nected to the flow-regulating valve.

Preferably the machine has a beam arranged to be raised and lowered by hydraulic means in-.- cluding a piston operating in a double en'ded cylinder, a control valve adapted to be set to direct pressure fluid to either end of the cyle inder at will and. to vary the rate ofvfiow of pressure fluid to the cylinder, said valve normally being set to direct pressure fluid into one end of the cylinder for raising the beam, means for setting the control valve to direct pressure fluid at a normal rate of flow to the other end of the cylinder for lowering the beam,- a first cam member adjustably mounted on the beam and adapted, when the beam reaches a selected distance from the bottomoi its stroke, to move 7 the control valve to a setting which reduces the t 1 claim, (01. 121-48) ra of flow o p su oflu to sa dlast-msm tiqnedend of the cylinder, sothat t e dow ward movement of the beam is then slowed down, and a second cam member carried by the be m a d d ed't est e the cont l valve o i s normal set n when t e eam e hes th bo tomo i "pre ined stroke s th m em nt oi he eam s t en rev rse A embodiment o t i ention wi l ow desc ib d by way of xa p e with eferen o t ccompanyin d awin s, n which;

' i 1 is a ron ew o the mac n Fig. 2 is an end view of Fig. l.

Fig. i a r gmen a y pla vi w.

his 4 e detail sec ion on n n or taken oh th l n V of Fig, 1;

Figis a detail s io n n e lar d, Scale taken on the line V-?-V of Fig. 2 @1 11 V F 6 is'an xplana dia ram The mainframe l of the machine carries the bed p a e 2 n wh ch h fix d be n l 3 is mounted, 'The' moving bending tool- 4 is moun ed, on the b am 5 hich is e on s de 6, I on the main frame so asto be movable towards and away from the bed plate 2. The bond n too is ad usta le relatively to t e beam 5 in known manne by a wo m ear 9 a d an. ass iated sha t 8 driven by an auxiliary Movem n o the beam 5 s ve n n identicai to gle-mechan sm ssoc ed, w t t two nds of the be m and a u imul neou v. The lowe ink, l2 o h t le s p tally' a ta he o. e a ociat d end i he beam 5 by a pivot pin 1L, t othe nd of t e lin I: being pivoted to th u e toggle l n 4, at the knee. 3 o he. to gl The p er o gle li I4 is pivoted intermediate its ds on a at onary pivot 5 provid d on the main tra s l of he mach Ths' t r nd o he link 14 is' connected by a pivot pin [6 to a connest n link i which at' its other nd' s ot d at 18 to a col ar S, The colla lis se u on a rod ZJPhrallel to the beam and slidable in its a ia direc on in uides i e main frame I One end o the ro 2 ar a pi ton operatinsin a c inder 22 mounted n the main. frame I. By thecontrolle'd admission of a; pres, sure fluid, such as o into t ylind r 2, the piston 2! is displaced together with the rod 20 and, in co s que e h beam s rai d and lowe e n the dra i gs, the machine s sh n wit he h amin t e ful rai ed o n, whi h is the normal position- To enable the operator to control the machine ed scale 35 is connected through a link 36 to the spindle 31 of a four-way valve 38.

The latch member 36 co-operates with a cam 39 carried by the beam, so that when the beam reaches the bottom of its stroke the cam 39 actuates the latch member 36 to release the con-.

nection between the rocking lever 29 and the trip lever 3|.

The end of the rocking lever 29 nearest the beam is cranked downwardly and carries a follower roller46 which co-operates with a cam 4| mounted in slides on the beam 5. (See Fig. 4.) The cam 4| is formed on one side with a rack 43 which is engaged by a pinion 44 mounted on a shaft 45 journalled in the beam 5. A lever 46 mounted on the outer end'of the shaft 45 moves over a calibrated dial 48 andmay be set in any desired position by a spring-loaded detent '41 which may engage in any one of a number of depressions 49 (see Fig. 1) in the calibrated dial 48. By operating the lever 46 the cam 4| may be adjusted vertically with respect to the beam. The cam 4| is arranged to actuate the rocking lever 29 at a selected distance from the bottom of the stroke of the beam 5, rocking this lever clockwise as viewed in Fig. 4 and transmitting motion through the latch member 36, trip lever 3|, link member 32, levers 33 and 35 and link 36 to raise the spindle 31 of the four-way valve The power for moving the rod 20 is derived from a rotary pump 56 which is connected to its driving electric motor by way of a flexible coupling, 52. The pump56 draws oil from a reservoir 53 through an inlet 54 provided with filters 55 to prevent foreign matter entering the pump with the oil. From the pump 56 the oil is delivered by way of a relief valve 56, serving to limit the maximum oil pressure, to the central inlet port 51 of the four-way valve 38.

Referring more particularly to Fig. 5, the spindle 31 of the valve 38 is formed with valve heads 58 and59 intermediate its length. As the spindle 31 slides, the valve head 56 moves between valve seats 66 and 6| whilst the valve head 53 moves between valve seats 62 and 63. The valve is provided with five ports in all. The port 65 is separated from the central inlet port 51 by the valve seat 6| and from the port 64 by the valve seat 66. The port 66 is separated fromthe central inlet port 51 by the valve seat 62 and from the port 68 by the valve seat 63.

In the normal position of the press in which the beam is stationary in the raised position, the valve spindle 31is held in the upper position shown in Fig. 5 by a spring 69. In this position the port 65 is in communication with the central inlet port 51 and is shut off from the port 64. When the valve spindle 31 is fully. depressed against the action of the spring 69, the port 65 is placed in communication with the port 64 and shut-01f from the central inlet port 51, whilst the port 66 is placed in communication with the central inlet port 51 and is shut off from the port 68.

The port 65 leads by way of a check valve 1| to an inlet 13 at the end of the cylinder 22 at which oil is admitted for raising the beam 5. When the piston 2| is in the position corresponding to the fully raised position of the beam 5, i. e. in the raised position as shown in the drawings, it exposes a port 12 which is thereby placed in communication with the inlet 13. A conduit leads from the port 12 by way of a non-return valve 14 to the port 66 of the four-way valve which in this setting is in communication with the port 68 of the four-way valve 38. The port 68 and the port 64 are bothconnected to a, common return pipe 16. from the inlet 13 the cylinder is provided with an inlet 15 which is connected to the conduit between the non-return valve 14 and the port 66 of the four-way valve. At the same end as the inlet 15, the cylinder 22 is provided with an outlet 16 from which a conduit leads by way of an escape valve 11 to the reservoir 53 by way of a conduit 18. The escape valve 11 is controlled by the fluid pressure in the conduit between the port 65 of the four-way valve and the check valve 1| so that when the beam is being raised, 1. e.'during movement of the piston 2| to the right in Fig. 6, the valve 11 is opened to give free escape of the oil in front of the piston. Owing to the constant delivery of the pump 50 and the smaller piston area for this movement of the piston the return stroke of the beam is faster than the working stroke. The connection to the cylinder 22 of a vent 19 serves to allow the escape of any air bubbles which may enter the hydraulic system, being arranged in a well-known manner to check escape of operating fluid. A bleeder valve 86 (see Fig. 6) may be used for draining the cylinder 22 when required.

In the operation of the device the cam member 4| is adjusted vertically with respect to the beam 5 by means of the lever 46 to slow down the beam at a distance from the bottom of its stroke which is selected according to the character of the bending tools and the nature and thickness of the plate or sheet to be bent. The operator then depresses the pedal 24 and the motion is transmitted through the linkage described to depress the spindle 31 of the four-way valve 38. The pump delivery is directed from the centralinlet port 51 of the four-way valve through the port 66 to the cylinder 22 at the inlet 15, so that the piston is urged to the left and the beam 5 is driven down by the toggles ||-|8. The oil expelled from the left-hand side of the cylinder flows through the port 65 of the four-way valve to the port 64 and thence to the return conduit 10; When the beam 5 reaches the selected distance from the bottom of its stroke, the cam 4| rocks the lever 29 clockwise as viewed in Fig. 4 and the motion of the rocking lever 29 is transmitted to the valve spindle 31 to raise the latter somewhat, thus restricting the communication between the central inlet port 51 and the port 66 of the four-way valve and thus reducing the rate of flow of pressure oil to the inlet 15 of the cylinder 22. The downward motion of the beam is slowed down accordingly.

When the beam 5 reaches the bottom of its stroke, the cam member 39 actuates the latch member 36 to release the trip lever 3| from the rocking lever 29. The spring 69 of the four-way valve can now re-assert itself moving the valve spindle 31 back to the normal position shown in Fig. '5. The oil under pressure is now delivered from the central inlet port 51-to the port 65 of the four-way valve and thence to the inlet 13 of the cylinder 22 so that the piston 2| is driven At the end of the cylinder 22 remote,

to the right to raise the beam. The pressure in the delivery conduit from the port 65 to the inlet 13 causes the valve 11 to open so that the oil in front of the piston can escape through this valve as well as by way of the cylinder inlet 15 and the ports 66 and 68 of the four-way valve to the return conduit 10. When the piston 2| reaches the end of its travel it exposes the port 12 so that the oil supplied from the pump to the inlet 13 is discharged from the port 12 of the cylinder via the ports 66, 68 of the four-way valve to the return conduit 10. This completes the cycle of operations which can be re-initiated by actuating the pedal 24 or hand lever 25.

What I claim is:

A hydraulic system for raising and lowering the tool carrying beam of a machine for bending sheets and plates of metal, comprising a doubleended cylinder, a piston movable in said doubleended cylinder and operatively connected to said beam to raise and lower the same with a predetermined stroke, a source of pressure fluid, a return conduit, a four-way control valve connected to said source of pressure fluid, said cylinder and said return conduit, a movable valve member within said valve, a spring for urging said movable valve member into one extreme position, which is the normal position, to place the end of said cylinder for raising said beam in communication with said source of pressure fluid and to place the other end of said cylinder in communication with said return conduit, said movable valve member being movable into a second extreme position, which is the operative position, the place said first-mentioned end of said cylinder in communication with said return conduit and to place said other end of said cylinder in communication with said source of pressure fluid, initial movement of said movable valve member from said operative position towards said normal position being operative to reduce the flow of liquid to said other side of said cylinder, a control lever, a rocking lever operatively connected to said control lever, a latch member releasably connecting said rocking lever to said movable valve member, said control lever beingmovable to set said movable valve member in said operative position so as to initiate downward movement of said beam, a first cam member-adjustably mounted on said beam and adapted, when said beam reaches a selected distance from the bottom of its stroke, to actuate said rocking lever to impart to said movable valve member initial movement from said operative position towards said normal position, so that the downward movement of said beam is slowed down, and a second cam member carried by said beam and adapted, when said beam reaches the bottom of its predetermined stroke, to release said movable valve member from said rocking lever and thus permit said movable valve member to be restored by spring action to said normal position, whereby movement of said beam is then reversed.

CHARLES JOSEPH RHODES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,685,049 Galloway Sept. 18, 1928 1,750,684 Oakley Mar. 18, 1930 2,192,778 Stacy Mar. 5, 1940 ,210,665 Harrington Aug. 6, 1940 2,368,017 Grad Jan. 23, 1945 2,426,411 Peterson et al Aug. 26, 1947 

